Precision industrial fluid-flow control mechanisms, such as pneumatic gripping devices, typically employ some form of pneumatic (or electropneumatic) valve for controlling the flow of a working fluid (e.g. air in a vacuum system) to a controlled pressure region, such as a venturi associated with a vacuum pick-up head of a seizure/transport tool. One example of such a mechanism is the pneumatic vacuum gripper system described in my U.S. Pat. No. 4,750,768 issued June 14, 1988. In accordance with the structure and operation of the patented system, fluid-flow through a main venturi vacuum generator is selectively controlled, in order to ensure the application of a vacuum to a pick-up head as necessary to seize and grip an object.
In conventional industrial applications, the various units that make up an overall system are customarily stand alone devices interconnected using numerous `plumbing` conduits and fixtures to realize an overall system functionality. While the availability of different types of parts from a variety of sources offers the system designer a wide choice of system configuration, the production of customized interface components is often required, which keeps costs high and often results in an implementation that suffers from weight and space penalties, thereby restricting multiple application usage.
To obviate these shortcomings of conventional `patch work`-configured pneumatic vacuum gripping systems, I have invented a new and improved electropneumatic device in which a vacuum head venturi and an associated electropneumatic fluid-flow control valve are integrated together in a compact modular assembly that readily lends itself to a variety of gripping and transport applications, without imposing space/weight constraints on the host industrial system. This inventive device, which is the subject matter of my copending U.S. patent application Ser. No. 342,305, entitled "Electropneumatic Vacuum Supply Assembly", filed on even date herewith, is formed of a multiport modular unit, to which fluid supply, exhaust and vacuum lines may be coupled, for providing an electropneumatically-controlled vacuum to an attendant gripping head.
In particular, the device is configured as an integrated assembly that houses both a venturi and solenoid-operated fluid-flow control valve unit. The valve unit contains a solenoid device, which is coupled with a translatable spool valve element, for controlling the displacement of the valve element and thereby fluid communication between fluid inlet and fluid outlet ports through the venturi. Miniaturization and simplicity of the unit is facilitated by the design of the solenoid unit which employs a steel bearing ball as its movable armature. Namely, by paying special attention to the structural configuration and cooperation among the hardware components of the system, I have been able to implement all of its functionality in an integrated arrangement that readily lends itself to multiple utility applications and permits the units to be easily interfaced with a variety of existing fluid flow control system designs.